A driveline disconnect clutch may be used to selectively couple and decouple components of a vehicle driveline. The driveline disconnect clutch may be placed between two different torque sources to allow the torque sources to operate independently or together based on vehicle operating conditions. In one example system, a driveline disconnect clutch is placed in a driveline at a location between an engine and an electric machine. The electric machine may be directly mechanically coupled to a transmission. The driveline disconnect clutch may be partially closed to allow the electric machine to crank the engine during engine starting. The engine may be started in response to a driver demand torque or based on other conditions not related to driver demand torque. However, if the engine is not started in a timely manner in response to driver demand torque, the driver may be disappointed with the vehicle's performance.
The inventors herein have recognized the above-mentioned disadvantages and have developed a driveline method, comprising: increasing driveline disconnect clutch working fluid pressure in response to a rate of change in accelerator pedal position.
By increasing and/or adjusting pressure of a working fluid supplied to a driveline disconnect clutch in response to a rate of change in accelerator pedal position, it may be possible to provide the technical result of improving vehicle launch performance while providing acceptable driveline noise, vibration, and harshness (NVH). In particular, a driveline disconnect clutch may be closed at a faster rate via increasing pressure of the working fluid supplied to the driveline disconnect clutch during conditions where the rate of increase in accelerator pedal position indicates an urgency to provide torque to vehicle wheels. On the other hand, if the rate of accelerator pedal position change is low, the pressure of working fluid supplied to the driveline disconnect clutch may be reduced to provide a smoother engine start with lower NVH.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.